Journal Article

FZJ-2019-02814

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Chemical control of the electrical surface properties in donor-doped transition metal oxides

Andrä, M. (Corresponding author)FZJ* ; Bluhm, H.FZJ* ; Dittmann, R.FZJ* ; Schneider, C. M.FZJ* ; Waser, R.FZJ* ; Müller, D.FZJ* ; Gunkel, F.FZJ*

2019
APS College Park, MD

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Please use a persistent id in citations: http://hdl.handle.net/2128/22132  doi:10.1103/PhysRevMaterials.3.044604

Abstract: Donor-doped transition metal oxides such as donor-doped strontium titanate (n−SrTiO3) are of fundamental importance for oxide electronic devices as well as for electronic surface and interface engineering. Here we quantitatively analyze the variable band alignment and the resulting space charge layer at the surface of n−SrTiO3, determined by its surface redox chemistry. Synchrotron-based ambient-pressure x-ray photoelectron spectroscopy conducted under applied thermodynamic bias is used to access electronic structure and chemistry of the surface. We find an electron depletion layer driven by cationic surface point defects that are controlled by adjusting the ambient atmosphere (pO2). We correlate the pO2 dependence to a response of the strontium sublattice, namely the precipitation of strontium oxide and the formation of charged strontium vacancies at the surface. We suggest the reversible conversion of surface-terminating strontium oxide into extended strontium oxide clusters as the responsible process by resolving chemical dynamics in situ. As we show, atomic control of these subtle changes in the surface redox chemistry allows us to tailor electrical transport properties along the n−SrTiO3 surface. Our study thereby gives access to engineering electronic band bending in transition metal oxides by the control of the surface chemistry.

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Contributing Institute(s):

1. Elektronische Materialien (PGI-7)
2. JARA-FIT (JARA-FIT)
3. JARA Institut Quanteninformation (PGI-11)
4. Elektronische Eigenschaften (PGI-6)

Research Program(s):

1. 524 - Controlling Collective States (POF3-524) (POF3-524)

Appears in the scientific report 2019

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Database coverage:
; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; IF < 5 ; JCR ; Science Citation Index Expanded ; Web of Science Core Collection

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